Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 241904
AFDRAH

Area Forecast Discussion
National Weather Service Raleigh NC
300 PM EDT SUN JUL 24 2016

.Synopsis...
Strong high pressure aloft will extend across the region through
early Wednesday, bringing a period of hot and humid conditions to
central NC. The chances for afternoon storms will increase by
mid week.

&&

.Near Term /through tonight/...
As of 225 PM Sunday...

Convection chances remain small the rest of today into tonight,
given the very warm mid level temps helping to curb instability
despite very warm surface temps and dewpoints. With very weak deep
layer shear and stacked high pressure over the area throughout the
mid and upper levels helping to deflect most moisture and
perturbations, except for perhaps an isolated storm or two along the
sea breeze, will keep pops very low and confined to the southeast
CWA for another few hours. The latest CAM runs support this minimal
coverage. Temps are still climbing through the 90s this afternoon
with very light winds, and dewpoints remain in the low-mid 70s in
most places, pushing heat index values to 100-108 across the heat
advisory area. Muggy conditions are expected tonight, with lows in
the 71-75 range. -GIH

&&

.SHORT TERM /Monday through Monday night/...
As of 255 PM Sunday...

More of the same, with very warm temps aloft (approaching 3 standard
deviations above normal) helping to limit instability and thus
suppress most convection, with very weak deep layer shear. The
stacked deep ridge axis will hold across NC, with a fairly dry
column persisting, although models do indicate some moistening aloft
just to our W and NW over the Appalachians. The HRRRX indicates
scattered storms developing over the NC mountains by late morning
Mon, and the larger-scale models support this, but with the very
weak steering flow, these cells should meander very slowly to the E
or SE during the afternoon, and may not quite reach the western CWA
before daytime heating wanes. Will stick with no pops for now,
although we may ultimately need a couple hours of isolated coverage
very late in the day over the Triad. Statistical guidance and
forecast thicknesses suggest highs once again in the mid-upper 90s,
and while dewpoints should mix out somewhat during the day (although
they did not mix out much today especially in the eastern CWA due in
part to the very light low level winds), the heat index values are
still likely to exceed 100 degrees over the eastern two-thirds of
the forecast area, with some spots reaching or exceeding 105. Even
if values don`t quite reach 105 Mon, the lack of much recovery at
night (temps holding at 75-80 for a good portion of the nighttime
hours) and the multiple successive days of hot/humid weather still
support a heat advisory for tomorrow. Will place the advisory along
and east of a line from Wadesboro to Siler City to Hillsborough to
Roxboro. We should see the stagnant surface air of the last few days
pick up a bit from the SW during the afternoon. Lows Mon night
should once again be in the low-mid 70s. -GIH

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
As of 210 PM Sunday...

A low pressure system over eastern Canada moves offshore on Tuesday
and leaves behind a frontal zone just north of the area. This
boundary is not expected to move much for several days as high
pressure over the southeast and westerly flow aloft maintain a hot
and fairly stagnant pattern over central NC. The Piedmont trough is
the only discernible boundary that remains over the area and could
be the focus of some afternoon convection but not much in the way of
severe weather to speak of. Wednesday and Thursday afternoons
feature the best instability and shear comes up a little bit by late
Thursday afternoon above 20 knots but confidence and timing at this
point are very low.

What is confident is that temperatures will remain hot with highs in
the mid 90s every day through the long term and lows in the mid 70s.
Dewpoints will also continue to be in the 70s. This will result in
heat index values close to heat advisory criteria, especially in the
south and east each day.

&&

.Aviation /18Z Sunday through Friday/...
As of 135 PM Sunday...

VFR conditions are likely to dominate through Monday afternoon.
Strong, dry, and deep high pressure in the middle and upper levels
of the atmosphere will hold overhead for the 24 hours and beyond,
leading to minimal cloudiness (scattered daytime cumulus based above
4 kft) and little to no chance of storms. Light fog (MVFR) is
possible mainly at RWI/FAY late tonight into Mon morning, and
isolated banks of shallow, more dense fog may occur, mainly near
RWI. Surface winds will stay light and variable through tonight
before becoming southwesterly at 6-10 kts.

Looking beyond 18z Mon: An extended period of mostly VFR conditions
is anticipated. One exception will be in the late night and early
morning hours each day this week, when pockets of sub-VFR fog are
possible. Storm chances will remain fairly low through Tue, then
increase Wed through the end of the work week. -GIH

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for NCZ010-011-025>028-
040>043-075>078-084>086-088-089.
Heat Advisory from noon to 8 PM EDT Monday for NCZ007>011-
024>028-040>043-074>078-083>086-088-089.

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Hartfield
LONG TERM...Ellis
AVIATION...Hartfield



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